Nick Kyrgios has pulled out of the US Open doubles, bringing an end to a disappointing 2019 grand slam season.

Kyrgios and Marius Copil were scheduled to play Jurgen Melzer and Oliver Marach in the second round on Sunday, but the Australian No.1 withdrew citing an elbow injury.

The controversial Australian will now await the outcome of two separate ATP investigations into his conduct in Cincinnati and New York over the past three weeks.

He faces potential bans of up to 12 months for the two “major offences” – calling Irish umpire Fergus Murphy a “potato” and “f…ing tool” and spitting in his direction in Cincinnati and subsequently accusing the ATP of being “pretty corrupt” after they slapped him with a $US113,000 ($A167,704) fine.